Photo: James Gathany, CDC
The Texas Department of State Health Services (DSHS) announced on July 7, 2014, that the first human case of chikungunya in the state of Texas had been confirmed in Williamson County. According to provisional data by the U.S. Centers for Disease Control and Prevention (CDC), there were a total of 2,492 laboratory-confirmed chikungunya cases reported in the United States in 2014, with 81 of those cases occurring in Texas. These numbers will most likely be higher when all the data are finalized.
Chikungunya is caused by the chikungunya virus, which is transmitted between humans primarily through the bite of two mosquito species: Aedes aegypti and Aedes albopictus. Aedes aegypti often inhabits urban areas and dwellings, while Aedes albopictus is commonly found in surrounding natural habitats. Aggressive daytime biters, these mosquitoes are most active in the early morning and late afternoon.
All of the chikungunya cases in Texas up to this point have been imported, which means that the individuals diagnosed in Texas were infected with the virus in another country. However, both Aedes aegypti and Aedes albopictus are found in Texas, which increases the likelihood of local person-to-person transmission. With the disease spreading throughout the Americas and the Caribbean, the number of chikungunya cases in Texas is expected to rise this summer.
While some individuals who become infected with the chikungunya virus are asymptomatic and remain undiagnosed, those who manifest symptoms usually do so between three to seven days after infection. The primary clinical symptoms of chikungunya are fever and severe polyarthralgia, or multiple joint pain. The individual may also exhibit additional symptoms, such as headache, muscle pain, conjunctivitis, nausea, vomiting, and/or a maculopapular rash. Symptoms typically abate within a week, although joint pain may persist for weeks, months or even years.
In the state of Texas, infection by an arbovirus (arthropod-borne virus), including chikungunya, is a reportable disease, and confirmed and suspected cases must be reported within one week. The Texas Health and Safety Code, Section 81.042 includes emergency medical services personnel, peace officers and firefighters in the list of persons required to report to the local health authority a suspected case of a reportable disease and all information known concerning the person who has or is suspected of having the disease. To access reporting forms and contact details for the local health authority, go to http://www.dshs.state.tx.us/idcu/investigation/conditions/contacts/ and click on the name of the appropriate county.
There are currently no specific antiviral drugs available to treat chikungunya, so the primary way to combat the disease is through prevention and education. The Texas Department of State Health Services recommends that citizens be encouraged to wear long-sleeved shirts and pants, use mosquito repellent on exposed skin during the times that the mosquitoes are most active, keep door and window screens in good repair and drain standing water from outdoor containers.